1. Field of the Invention
The present invention relates to ink jet printers, and, more particularly, to a wiping assembly for wiping a nozzle plate in an ink jet printer.
2. Description of the Related Art
An ink jet printer typically includes an ink jet cartridge assembly with a printhead mounted under a body. The body includes one or more ink reservoirs which are in fluid communication with the printhead. The printhead includes a plurality of heaters which are respectively positioned in association with nozzles in a nozzle plate. The heaters are selectively actuated during printing to jet ink droplets from the corresponding nozzles in the nozzle plate.
The nozzle plate and nozzles may become contaminated over time as a result of ink residue and other contaminants which accumulate adjacent the nozzles as a result of printing operations. Such contamination may reduce print quality or entirely prevent printing. It is thus known to periodically clean the nozzle plate to remove contamination therefrom.
A conventional wiping assembly for cleaning a nozzle plate includes a wiping blade which is positioned in association with the nozzle plate. The wiping blade includes a linear wiping edge which contacts and cleans the nozzle plate as the ink jet cartridge assembly is moved past the wiping blade during a cleaning operation. A problem with this type of wiping assembly is that the contamination removed from one part of the nozzle plate may be smeared and deposited on another part of the nozzle plate. More particularly, as shown in FIG. 1, a nozzle plate typically includes multiple arrays of ink jetting nozzles which are positioned generally parallel to each other and transverse to the scan direction of the nozzle plate. As the nozzle plate is moved in a scan direction through the cleaning station to contact the wiper blade, the wiping edge of the blade contacts a first array of the nozzles in the nozzle plate. The ink residue and other contaminants removed from the first array of nozzles remain on the wiping edge of the wiper blade. As the ink cartridge assembly continues to move past the wiper blade, the ink residue and other contaminants may be smeared and/or deposited on an adjacent array of nozzles. Moreover, the ink residue and other contaminants may in fact fill or clog other nozzles in the nozzle plate, thereby resulting in poor print quality.
It is also known to use a rotary wiper to remove contaminants from a nozzle plate in an ink jet cartridge assembly. Such rotary wipers include a pair of flexible blades which only intermittently contact the nozzle plate. The intermittent contact provided by the flexible blades may not effectively clean the nozzle plate. Moreover, the flexible blades wipe multiple arrays of nozzles before the blades are cleaned, thereby possibly resulting in contamination of adjacent arrays of nozzles the same as described above when using a linear wiper blade.
What is needed in the art is a wiper assembly for wiping a nozzle plate in an ink jet printer which effectively removes ink residue and contaminants while preventing cross-contamination of adjacent nozzle arrays.
The present invention provides a wiping assembly for an ink jet printer including a rotary wiper with a helical-shaped wiping edge which moves with a tangential velocity greater than the scan velocity of the ink jet cartridge assembly.
The invention comprises, in one form thereof, an ink jet printer for printing on a print medium, including an ink jet cartridge assembly movable at a scan velocity in scan directions. The ink jet cartridge assembly includes a nozzle plate. A rotary wiper is positioned in association with the nozzle plate for contacting the nozzle plate. The rotary wiper is rotatable with a tangential velocity which is greater than the scan velocity.
The invention comprises, in another form thereof, an ink jet printer for printing on a print medium. The ink jet printer includes an ink jet cartridge assembly with a nozzle plate. A rotary wiper is positioned in association with the nozzle plate. The rotary wiper has a radially outwardly extending wiping edge for contacting the nozzle plate. The wiping edge has a generally helical shape about the rotary wiper.
An advantage of the present invention is that the rotary wiper moves with a tangential velocity which is greater than a scan velocity of the ink jet cartridge assembly, thereby preventing transfer of the ink residue and other contaminants from one nozzle array to an adjacent, parallel nozzle array.
Another advantage is that the rotary wiper is formed with a helical wiping edge which allows continuous rotary motion.
A further advantage is that a helical wiping edge may be configured with a flat, curved, etc. distal contacting surface.